The invention relates to a filling material for percolating filters for the treatment of liquids, especially for biological sewage purification. Furthermore, the invention relates to a process for producing filling material and to a process for assembling the filling material.
The filling bodies discussed here are used mainly for biological treatment in sewage disposal. They serve to receive the bacteria necessary for biological treatment, in particular a so-called filter film. At the same time, the efficiency of a percolating filter equipped with filling material depends on the specific growth area, the hold of the bacteria on this and the all-round unimpeded wetability of the filter film on the filling material by the liquid to be treated.
Filling materials of the relevant generic type, in which a plurality of plastic strips or plastic filaments are suspended, either individually or in bundles, on bars or beams of the supporting arrangement, are already known. A disadvantage of this is that the production of the known percolating filters made with this filling material involves a high outlay, specifically particularly when these have to be suspended individually on the supporting arrangement. Furthermore, when the filling material is suspended individually on the supporting arrangement there is no guarantee that it will be distributed uniformly in the percolating filter as a whole. Finally, the strips or filaments of this known filling material often do not hang securely enough on the bars or beams of the supporting arrangement.